Forgotten Clause

Before a player casts a spell, they must say
"Within the confines of the law...". If they do
not, you may counter target spell. When you do,
sacrifice this artifact. While in play, you may have
this spell in play outside the play area, face down
or otherwise hidden, as long as it is within arms
reach of your library. If it is not in play, keep
this spell where it would normally be kept.
"They never read the fine print..."